Vehicle Head-Up Display Brightness Adjustment for Visual Distance
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Solution Overview
Problem
Existing display systems for vehicles, such as Head-Up Displays, face issues with reduced display quality and visibility when changing the visual distance between the observer and the virtual image, as simply moving the lens forward or backward can lead to discomfort and perceived changes in luminance.
Innovation Solution
A display system with an image producing unit, a projection unit, and an adjustment unit that adjusts the brightness of the virtual image according to the visual distance, using a controller to manage the size and luminance of the image displayed on a liquid crystal panel and the light source, ensuring constant display field angle and luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the lens is merely moved forward or backward to change the visual distance, then the visual distance between the virtual image and the observer is changed, but the observer may feel uncomfortable as if the luminance of the virtual image has changed, reducing display quality and visibility
Solution Approach 1:
The patent applies parameter changes by adjusting the luminance of the light source in response to changes in visual distance. When the visual distance is increased, the luminance is increased proportionally to maintain constant perceived brightness. This is achieved through a control unit that calculates the required luminance adjustment based on the ratio of visual distance changes, thereby resolving the contradiction between changing visual distance and maintaining luminance consistency.
2Length of moving object
If the lens is merely moved forward or backward to change the visual distance, then the visual distance between the virtual image and the observer is changed, but the display quality and visibility of the virtual image are reduced
Solution Approach 1:
The patent maintains display quality by dynamically adjusting the luminance parameter of the light source based on visual distance changes. The control unit calculates the luminance adjustment ratio based on the visual distance change ratio, ensuring that the perceived brightness remains constant. This parameter adjustment ensures reliable and comfortable display quality across different visual distances.
3Illumination intensity
If the luminance of the light source is kept constant, then the display quality is maintained, but the observer feels uncomfortable as if the luminance of the virtual image has changed when visual distance is altered
Solution Approach 1:
The patent changes the luminance parameter of the light source in response to visual distance changes to maintain observer comfort. The control unit adjusts the luminance based on the visual distance change ratio, ensuring that the perceived brightness of the virtual image remains constant. This dynamic parameter adjustment eliminates the uncomfortable sensation of luminance change for the observer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution maintains consistent display quality and visibility by adjusting the brightness and size of the virtual image as the visual distance changes, preventing discomfort and blurriness, thus enhancing the user experience.
Implementation Method 1
a liquid crystal panel having a display surface and configured to produce an image on the display surface
Implementation Method 2
a projection unit configured to project a virtual image to a target space with an output light of the image producing unit
Implementation Method 3
a reflective member configured to reflect light emitted from the projection unit
Data Source
AI summary
A display system includes an image producing unit, a projection unit and an adjustment unit. The image producing unit has a display surface, and is configured to produce an image on the display surface. The projection unit is configured to project a virtual image to a target space with an output light of the image producing unit. The virtual image corresponds to the image produced by the image producing unit. The display system is configured to change a visual distance between an eye-box and the virtual image. The adjustment unit is configured to adjust brightness of the virtual image according to the visual distance.